#ifndef __M_CHANNEL_H__
#define __M_CHANNEL_H__

#include"logger.hpp"
#include <brpc/channel.h>
#include <string>
#include <iostream>
#include <vector>
#include <mutex>

namespace xchat
{
//1.封装单个服务的信道管理类
class ServiceChannel
{
public:
    using ChannelPtr = std::shared_ptr<brpc::Channel>;
    using ptr = std::shared_ptr<ServiceChannel>;
    ServiceChannel(const std::string &name)
        :_service_name(name)
        ,_index(0)
    {

    }
    //服务上线了一个节点 则调用append新增信道
    void append(const std::string &host)
    {
        brpc::ChannelOptions options;
        options.connect_timeout_ms = -1;
        options.timeout_ms = -1;
        options.max_retry = 3;
        options.protocol = "baidu_std";
        auto channel = std::make_shared<brpc::Channel>();
        int ret = channel->Init(host.c_str(), &options);
        if (ret == -1)
        {
            LOG_ERROR("初始化{}-{}信道失败！", _service_name, host);
            return;
        }
        
        std::unique_lock<std::mutex> lock(_mutex);
        _hosts.insert(std::make_pair(host, channel));
        _channels.push_back(channel);
    }
    //服务下线了一个节点 则调用remove释放信道
    void remove(const std::string &host)
    {
        std::unique_lock<std::mutex> lock(_mutex);
        auto it = _hosts.find(host);
        if(it == _hosts.end())
        {
            LOG_WARN("{}-{}节点删除信道时, 没有找到信道信息!",_service_name, host);
            return;
        }
        for(auto vit = _channels.begin(); vit != _channels.end(); vit++)
        {
            if(*vit == it->second)
            {
                _channels.erase(vit);
                break;
            }
        }
        _hosts.erase(it);

    }
    //RR轮转策略 获取一个Channel用于发起对应服务的Rpc调用
    ChannelPtr choose()
    {
        std::unique_lock<std::mutex> lock(_mutex);
        if(_channels.size() == 0)
        {
            LOG_ERROR("当前没有能提供服务的节点");
            return ChannelPtr();
        }
        int32_t idx = _index++ % _channels.size();
        return _channels[idx];
    }
private:
    std::mutex _mutex;
    int32_t _index; //当前轮转下标计数器
    std::string _service_name;  //服务名称
    std::vector<ChannelPtr> _channels; //当前服务对应的信道
    std::unordered_map<std::string, ChannelPtr> _hosts; //主机地址与信道映射关系
};

//总体的服务信道管理类
class ServiceManager
{
public:
    using ChannelPtr = std::shared_ptr<brpc::Channel>;
    using ptr = std::shared_ptr<ServiceManager>;
    ServiceManager()
    {

    }
    //获取指定服务的节点信道
    ChannelPtr choose(const std::string &service_name)
    {
        std::unique_lock<std::mutex> lock(_mutex);
        auto sit = _services.find(service_name);
        if (sit == _services.end())
        {
            LOG_ERROR("当前没有能提供{}服务的节点", service_name);
            return ChannelPtr();
        }
        return sit->second->choose();
    }
    //先声明 我关注哪些服务的上下线 不关心的就不需要管理了
    void declared(const std::string &service_name)
    {
        std::unique_lock<std::mutex> lock(_mutex);
        _follow_services.insert(service_name);

    }
    //服务上线时调用的回调接口 将服务节点管理起来
    void onServiceOnline(const std::string &service_instance, const std::string &host)
    {
        std::string service_name = getServiceName(service_instance);
        ServiceChannel::ptr service;
        {
            std::unique_lock<std::mutex> lock(_mutex);
            auto fit = _follow_services.find(service_name);
            if(fit == _follow_services.end())
            {
                LOG_DEBUG("{}-{}服务上线了 但是并不关心", service_name, host);
                return;
            }
            // 先获取管理对象 没有则创建 有则添加节点
            auto sit = _services.find(service_name);
            if (sit == _services.end())
            {
                service = std::make_shared<ServiceChannel>(service_name);
                _services.insert(std::make_pair(service_name, service));
            }
            else
            {
                service = sit->second;
            }
        }
        if(!service)
        {
            LOG_ERROR("新增{} 服务管理节点失败！", service_name);
        }
        //防止重复锁
        service->append(host);
        LOG_DEBUG("{}-{}服务上线新节点， 进行添加管理！", service_name, host);
    }
    //服务下线时调用的回调接口 从服务信道管理中 删除指定节点信道
    void onServiceOffline(const std::string &service_instance, const std::string &host)
    {
        std::string service_name = getServiceName(service_instance);
        ServiceChannel::ptr service;
        {
            std::unique_lock<std::mutex> lock(_mutex);
            auto fit = _follow_services.find(service_name);
            if (fit == _follow_services.end())
            {
                LOG_DEBUG("{}-{}服务下线了 但是并不关心", service_name, host);
                return;
            }
            // 先获取管理对象 没有则创建 有则添加节点
            auto sit = _services.find(service_name);
            if (sit == _services.end())
            {
                LOG_WARN("删除{}服务节点时, 没有找到对象", service_name);
                return;
            }
            service = sit->second;
        }
        //防止重复锁
        service->remove(host);
        LOG_DEBUG("{}-{}服务下线新节点， 进行删除管理！", service_name, host);
    }
private:
    std::string getServiceName(const std::string &service_instance)
    {
        auto pos = service_instance.find_last_of("/");
        if(pos == std::string::npos) return service_instance;
        return service_instance.substr(0, pos);
    }
private:
    std::mutex _mutex;
    std::unordered_map<std::string, ServiceChannel::ptr> _services;
    std::unordered_set<std::string> _follow_services;       //关心的服务
};
}
#endif